Another way to sort this problem out is to leave the plant exactly where it is on it's post, cut it off above any rot, refill pot with good quality potting mix to just below the cut, and let nature do its thing. It will eventually throw out new roots which will head straight down into the potting mix and all is good. I realised this option when my dog to a liking to fresh dragonfruit stems and ate about 12 inches of stem from one of my 1 year old plants. I did nothing, and the ariel roots kept it going until the chewed off base threw out 3 roots. They grew all the way back to the soil(in the air, not touching the post) and the plant is growing strong. Hope this helps.